Insulating bushing for a lead-in conductor to a capacitor housed in a vessel containing a gas under pressure



June 6, 1950 c. DE LANGE INSULATING BUSHING FOR A LEAD-IN CONDUCTOR TO A CAPACITOR HOUSED IN A VESSEL CONTAINING A GAS UNDER PRESSURE Flled July 20, 1946 7 A //w/vron aae/va/s 0: mm:

5 y %4 W AGE N Patented June 6, 1950 INSULATING BUSHING FOR A LEAD-IN CON- DUCTOR TO A CAPACITOR HOUSED IN A VESSEL CONTAINING A GAS UNDER PRES- SURE Cornelis de Lange, Eindhoven, Netherlands, as-

signor to Hartford National Bank and Trust Company, Hartford, Conn., as trustee Application July 20, 1946, Serial No. 685,173 In the Netherlands February 17, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires February 17, 1963 5 Claims. 1

This invention relates to an electric device, more particularly a condenser placed in a gasfilled pressure vessel, a supply conductor of which is led through the wall of the vessel in a gastight and insulated manner by means of a ceramic intermediate piece and is supported outside the vessel by a lead-in insulator which concentrically surrounds the supply conductor and whose base is fastened to the wall of the vessel.

For improving the power factor in transmission lines use is frequently made of pressure condensers when large powers are concerned. In this case the condenser is housed in a pressure vessel filled with gas, for example nitrogen, up to a pressure of 20 atmospheres. The breakdown voltage and the security in operation of the condenser appreciably increases by the use of gas under pressure. In most cases such a construction utilises welded sheet steel for the pressure vessel. It is then necessary for at least one of the supply conductors to be led through the wall of the vessel in a gas-tight and insulated manner. A ceramic intermediate piece arranged in a gas-tight manner is particularly suitable for the purpose. To this type belongs the known glass-chrome iron lead-in device. In this case a chrome-iron cylinder is welded in an aperture of the wall, a chrome-iron ring being fastened on the supply conductor. The cylinder and the ring are now connected to each other by means of glass having a suitable coeflicient of expansion. This construction is not suficiently rigid without further expedients. Consequently, it is necessary for the supply conductor to be supported outside the vessel, so that any forces exerted thereon need not be taken up by the glass intermediate piece. For support use is frequently made of a lead-in insulator which concentrically surrounds the supply conductor and whose base is secured directly or indirectly to the wall of the vessel. The supply conductor is fastened in the lead-in insulator, so that forces exerted on the supply conductor are taken up by the lead-in insulator. The latter is of the known type and is made of porcelain.

Pressure condensers have the drawback of the danger of explosion. It is not diflicult for the vessel containing the condenser to be constructed so rigidly that the risk of breakage thereof is practically precluded. The glass intermediate piece necessary for the gas-tight and insulated entry of a supply conductor through the Wall forms, however, the weakest point of the vessel. If here pressure occurs, the lead-in insulator arranged outside the vessel will also be exposed to the pressure prevailing in the vessel. Since the dielectric losses must be small, this lead-in insulator has a small wall thickness, so that it cannot resist the high pressure which occurs in the case of breakage of the intermediate piece. The fragments of this insulator and of the glass intermediate piece will now be flung away by the force of the escaping gases. In this case there is a danger to apparatus which may be present and a risk of damage to the other parts of the installation in the vicinity of which the condenser is located.

The present invention has for its object to eliminate the said drawbacks by providing a construction which offers great safety.

According to the invention, the space located between the ceramic intermediate piece and the lead-in insulator is shut ofi from the atmosphere by means of a membrane which is not able to resist the pressure normally prevailing in the pressure vessel. If, now, breakage of the ceramic intermediate piece occurs, the space located between the intermediate piece and the lead-in insulator will be filled with gas under high pressure, so that the membrane will break down. The gases now break a way and the lead-in insulator is not exposed to a high pressure, so that any action of fragments is'avoided.

In one advantageous embodiment of the inven-' tion a saving in space is obtained wherein the membrane exhibits a flat annular shape and is secured between the supply conductor and the ring which concentrically surrounds the latter and is fastened to the lead-in insulator.

There is still a small possibility that the lead-in insulator breaks or at least is damaged by frag-- ments of the intermediate piece, which, when the latter is broken, are taken along by the gas flow. In one advantageous embodiment of the invention, in order to avoid or at least to reduce the action of fragments upon a lead-in insulator, a partition is arranged between a glass intermediate piece and the lead-in insulator and concentrically about the supply conductor. It has been found, that in the case of breakage this partition reduces the action of fragments in such manner that breakage of the lead-in insulator is no longer to be feared. However, it is also possible for this partition to be made from so tough a material and/or of such thickness that in the case of breakage of the intermediate piece it is completely resistant to the action of fragments.

It is evident that the partition must not prevent the passage of the gases. To this end, it may comprise apertures or it may not extend as partition must not necessarily exhibit excellent insulating properties whilst a decrease of the creeping distance is out of the question.

In order that the invention .may be more clearly understood and readily carriedinto efiect, it will be described more fully by reference to the accompanying drawing.

Fig. 1a is a cross-sectionalview-of the 'lead in construction according to the invention for -a pressure housed capacitor; and

Fig. 1b is a top view of the device shownin:

section in Fig. 1a

Referring to Fig. 1a, the steel wall I of-the vessel has a chrome-iron cylinder 2"welded in it. The latter is connected, by means of aglass intermediate piece 3, to a chrome-iron ring 4 soldered {to thesupply conductors which is thus led; through the. wall I in a gas-tight and insulated ..manner. To avoid spraying, screening ringsla, l9, Hand 2! are provided. Inorder to mechanically discharge the intermediate .piece 3,1.the .supplyconductor 511s supported outside the vesselbya lead-iniinsulator 6, the base l of whicheis fastened .to the wall l by means [of a flangeB of the chrome-iron cylinder .2. The lead-in insulator-,6 has arranged on it a metal ring-ii .which,vby means of a number -,of spokes l0, ll, l2 and I3 (see Fig' 1b), is connected to a ringi l4 .arranged on the supply conductor ,5. -The lead-in'iinsulator 6 takes up, via the spokes; the forces exerted on the supply conductor. .The membrane l issecured between the ring 9 and the supply-conductor 5. Between the inter mediate piece 3 and the lead-in insulator e" is arranged-the partition l6 whichexhibits an aperture I] provided concentrically about'the supply conductor-.5. -In the case oinbreakage of the intor-mediate piecei sfthepartition 16, which may be; for examplaof. a loweloss ceramic material, intercepts :the fragments, which may also result in. a breakage of the partition itself. Due to the pressureof the gases, the membrane i5 collapses, so .that :the lead-ein insulator 6 exposed to a slight over-pressure. Consequently, in the case ofabreakagerof the intermediate piece 3, externallymoiragments occur. Iithe partition ieis so proportioned .and/or manufactured from such material thatit does not break as a. result of breakage of :the intermediate-piece than additional advantage rmayzbeobtained by giving the resistance -;o flowingof the aperture li a high value relatively to that of theaperture closedby themembrane 15. Inthe case of .breakagethe greater partiof thedifference inpressure between the interior-and the exterior of the vessel then actsv-uponmthe aperture 1-7, and the remaining portion :011' the -aperture adjacent to the membrane I5. T The pressure in the space located between thepartition It and the insulator .6 thus remains .low.

@Gondensers according to the invention are completely ireefrom any action of fragments andithuszparticularly advantageous to be housed in*spaces in which operating staff must always be presehtzand/orvulnerable devices are arranged.

x 1. An: insulating e'bushing :for a lead-in conductor extending into :a :housing for 'a' condenser and the like'icentainingt a: gas under pressure comprising:an'iinsulating protective member .interposedebetweenuthe .wal1s...rof'i.the housing and the lead-in conductor, a gas-tight member interposed between lithe protective. member and the leade'in -conductor,. a hollow iinsulatingasupporting member exterior to and secured to the hous wing and concentric with the lead-in conductor which defines an enclosed space between it and the protective- 'member, and a collapsible memfbraneinterposed between the supporting mem- "berand thelea'diin conductor which collapses "member exceeds 1; that normally prevailing therein.

.ZiTAn insulating bushing for a lead-in con- .ductor extending into a housing for a capacitor and the like containing a gas under pressure comprisingan insulating protective member interposed between the walls of the housing and the .leacl-in conductor, a gas-tight member interposed between the protective member and leadin conductor, a hollow. dome-like insulating supporting member exterior to and secured to the housing and. concentric with the housin an annular ring-Ilike member ,securing said ,lead-in conductor to said supporting member, and acollapsible .member interposed between the ringlike member and the lead-in conductor which collapses when the pressure prevailing in the space ,b etweenl-. the supporting .member and the protective memberexceeds that normally prerailing therein.

.3.An' insulating bushing ,for a .lead-in conductor Whichextends. into ahousing for a capacitor and thelike containing a gas under pressure comprisingan insulating protective member interposed between the walls oi the housing and theJlead-in conductor, a gas-tight member interposed between-the protective member and the lead-in conductor. a hollowdome like insulating supportingimember exterior to and secured to .the housing and'tconcentric with the lead-in conductor, an. annular ringmember for securing the leadein conductor 1130 the supporting member, .a flat annular membrane interposed between the lead-in. conductor and the supporting member which collapses when the pressure prevailing in the .space between'the dome-like supporting memberand the protective memberexceeds that norm'ally prevailing.therein, and .aprotective partition concentric with. said leadeinconductor and interposed :between the latter and the protective imember.

insulating bushing .for .a lead-in conductor whichextendsinto a-housingfor acapac itor andthelike containinga gas under pressure, comprising aninsulating. protective. member interposed-rbetweentthe wa1ls;oi the housing .and the: lead inl conductor, a gas=tightmember interposed between the protective member and the lead-inxconductor, a ;-ho1i0W.-dome-like insulatillgz supporting-rmember exterior to and secured to-rthe housing and concentric with the lead-in conductor an annular wring-like member :for securing the lead-in "conductor to the supporting member, a flatiannularwmembrane interposed-between the ;l'eade'in conductor and the supporting member whichcollapses when .the :pressureain the space .:between the, supporting member .and the protect-i-veqmember exceeds .that normally prevailingithereim and;a protective. partitioninterposed between "the dead-in conductor and the protective smember having :an aperturetherein which is-;concentric :with: :the .lead-.in conductor.

25.1fm .gi'nsulating-ubushing.for a lead-in iconductorrwhich-iextendsintoaihousing-ion a capes:

itor and the like containing a gas under pressure comprising a ceramic member interposed between the walls of the housing and the lead-in conductor, a gas-tight member interposed between the ceramic member and the lead-in conductor, a hollow dome-like insulating supporting member exterior to and secured to the housing and concentric with the lead-in conductor, an annular ring-like member for securing the lead-in conductor to the supporting member, a flat annular membrane interposed between the ring-like member and the lead-in conductor which collapses when the pressure prevailing in the space between the supporting member and the protective member exceeds that normally prevailing therein, a partition of material resistant to fragmentation of the ceramic member interposed between the lead-in conductor-and the ceramic member and having an aperture therein concentric with the lead-in conductor and dimensioned to restrict the flow of gas there- 5 through when the ceramic member shatters.

CORNELIS DE LANGE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

